1. Field of the Invention
The present invention relates to a safety belt system, especially for automobiles and other motor vehicles. The system has a three-point safety belt, a self-locking belt reel-in mechanism which is mounted on a structural part of the vehicle, as well as, for the belt strap, a clamping mechanism which is disposed on the structural part of the vehicle and has at least one movable clamping jaw; the clamping mechanism is movably guided on the structural part of the vehicle, and is provided with a drive mechanism for this movement.
2. Description of the Prior Art
With one such safety belt system of the aforementioned general type, a piston/cylinder unit which is driven by pressurized gas is provided as the drive mechanism for the movement of the clamping mechanism along the structural part of the vehicle. The propellant charge of this piston/cylinder unit is actuated by a sensor which is associated with the vehicle. In this arrangement, by means of an appropriately provided connection of the piston/cylinder unit with the actuating member for the clamping mechanism, there is also assured that the clamping action of the clamping mechanism is indirectly triggered by the sensor. Appropriate design of the piston/cylinder unit initially provides for actuation of the clamping action, and only after a period of time brings about the longitudinal movement of the clamping mechanism accompanied by tensioning of the belt strap. After termination of the tensioning process, the clamping mechanism catches in a locking housing, so that the belt strap is not released when someone pulls on it again at the same time that the gas pressure in the drive unit for the clamping mechanism is reduced.
The purpose of such a safety belt system is, while eliminating the belt slack at the body of the person who is strapped in, to at the same time reduce the belt extension to such an extent that it is almost impossible for the strapped-in person to move forward.
An advantage of this heretofore known safety belt system is that as a result of clamping the safety belt in the vicinity of the guide fitting, the belt length which is subsequently still available for a possible extension, is now only two-thirds of the overall length of the three-point safety belt, thereby eliminating a considerable portion of the belt extension. At the same time, however, the belt strap is tightened or tensioned due to the longitudinal movement of the clamping mechanism, and the belt slack at the body of the person is therefore eliminated, whereby the tensioning force is considerably closer to the guide fitting, so that the entire force for eliminating the belt slack is available.
An object of the present invention is to further improve the safety belt system of the aforementioned general type, and in particular such that a dangerous forward movement of the body of a person which is strapped in is even more reliably avoided by means of a better adaptation of the geometrical position of the safety belt system to the body proportions of the person who is strapped in.